subterranean
adjective
sub·ter·ra·nean
ˌsəb-tə-ˈrā-nē-ən 
-nyən
variants
or less commonly subterraneous
ˌsəb-tə-ˈrā-nē-əs
-nyəs
1
: being, lying, or operating under the surface of the earth
2
: existing or working in secret : hidden
a subterranean network of criminals
subterraneanly
adverb
or less commonly subterraneously
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Go Underground With Subterranean
A tunnel is a subterranean road or pathway, and a subway is a subterranean railway. The subterranean vaults at Fort Knox hold billions of dollars of gold reserves. Subterranean reservoirs called aquifers are tapped for water; in places where the pressure on the subterranean water is great enough, a hole drilled in the ground will bring it bubbling to the surface.
Examples of subterranean in a Sentence
a subterranean bunker that supposedly could withstand even an atomic blast
Recent Examples on the Web
These subterranean passageways are significant in Hawaiian culture, providing shelter for the ancient communities and and being places for ceremonies and burials.
—
Kathleen Wong, USA Today, 20 May 2026
The new entrances to the museum are also designed to be subterranean and added to the Louvre’s moat, which itself will be turned into a garden designed by BASE, a French landscape agency.
—News Desk, Artforum, 19 May 2026
The Spa After a day of sightseeing, guests can retreat to the hushed, subterranean spa, with a Finnish sauna, hammam, and an intimate pool area cocooned under a curving ceiling.
—Alia Akkam, Travel + Leisure, 16 May 2026
The architecture of the subterranean pathways that funnel magma to the surface, the chemistry of the magma, the cadence of eruptions, and the assortment of eruption styles differ from place to place.
—Quanta Magazine, 8 May 2026
See All Example Sentences for subterranean
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Kathleen Wong, USA Today, 20 May 2026
The new entrances to the museum are also designed to be subterranean and added to the Louvre’s moat, which itself will be turned into a garden designed by BASE, a French landscape agency.
—News Desk, Artforum, 19 May 2026
The Spa After a day of sightseeing, guests can retreat to the hushed, subterranean spa, with a Finnish sauna, hammam, and an intimate pool area cocooned under a curving ceiling.
—Alia Akkam, Travel + Leisure, 16 May 2026
The architecture of the subterranean pathways that funnel magma to the surface, the chemistry of the magma, the cadence of eruptions, and the assortment of eruption styles differ from place to place.
—Quanta Magazine, 8 May 2026
See All Example Sentences for subterranean
Cite this Entry
“Subterranean.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/subterranean. Accessed 21 May. 2026.
Copy CitationKids Definition
subterranean
adjective
sub·ter·ra·nean
ˌsəb-tə-ˈrā-nē-ən
-nyən
1
: being, lying, or operating under the surface of the earth
2
: existing or working in secret : hidden
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